1. Field of the Invention
This invention relates to a novel polycyanoaryl ether and method for production thereof.
2. Description of the Related Art
At present, although the revolution for a material has been progressed in the worldwide scale, a synthetic polymer material such as plastics has still played a central role, and now are superior to metallic materials and inorganic materials in view of moldability and workability as well as in view of cost.
These plastics are usually classified into general-purpose plastics which have been widely used in commodities of belongings, and the like; engineering plastics having excellent performance particularly in the mechanical characteristics and heat-resistance; and super engineering plastics having more excellent performance than the engineering plastics. Among these plastics, the engineering plastics are a high performance polymer material having both excellent heat-resistance (such as a continuously using temperature of not less than 100xc2x0 C.) and high mechanical characteristics (including strength and elastic modulus). Such plastics have been established as an essential material in the industrial field including automobiles, electronic information, and precision instrument, and have been remarkably developed. A polyamide(nylon),an acetal resin, a polycarbonate, a polyester and a modified polyphenylene ether have been called as five typical engineering plastics.
The super engineering plastics have been developed for the purpose of improving the performance in the heat-resistance and mechanical characteristics as compared with conventional engineering plastics. The super engineering plastics have been receiving attention as a material capable of inviting the technological innovation in the wide industrial field including electronic information, precision instrument, and space aviation, following the general-purpose plastics and the engineering plastics.
This super engineering plastics have as a basic structure a polymer consisting of an aromatic skeleton. The related materials thereto include aramids (aromatic polyamides), polyethersulfones, polyarylates, polyphenylene sulfides, polyether ketones and polyetherimides, etc., and have successively been now commercialized.
In the meantime, aromatic polies ether nitrites (PEN) are one of materials to be expected as a super engineering plastic with excellent heat-resistance, hydrolysis-resistance and weatherability. Since these aromatic polies ether nitriles (PEN) contain a polar group, a cyano group, they excel also in adhesion properties to glass fibers, in addition to the above characteristics, and have used as a matrix for a composite material. The PEN which has been currently produced, however, has possessed such a problem as that the formation into a film, etc. is difficult due to the lack of solubility.
Therefore, an object of this invention is to provide a novel polycyanoaryl ether exhibiting excellent heat-resistance, hydrolysis-resistance and weatherability, as well as industrially high general-purpose properties, and the method for the production thereof.
Another object of this invention is to provide a novel polycyanoaryl ether having improved solubility in addition to the above-mentioned properties, and the method for the production thereof.
The present inventors have made diligent study in order to overcome the above problems, to find that by introducing a fluorine atom into an aromatic polyether nitrile, the cohesion between the main chains thereof would be weakened, and consequently the product can obtain the solubility. Further, the present inventors have also found that the polycyanoaryl ether thus obtained, because of its low polarizability of the Cxe2x80x94F binding, can be expected to attain the improvement of the transparency and the decrease in the hygroscopicity, as well as the various properties as mentioned above and also expected to have the heat-resistance and the radiation resistance improved due to the bond dissociation energy of the Cxe2x80x94F binding greater than that of the Cxe2x80x94H binding. Accordingly, they have found that the introduction of a fluorine atom allows giving the solubility without deteriorating the original properties, thus the development of a new high performance material excelling to conventional PENs can be expected, while the introduction of a fluorine atom can decrease a dielectric constant of a material, which material can be expected to be applied as an electronic material.
Specifically, these objects can be accomplished by a polycyanoaryl ether represented by the formula (1): 
wherein R1 stands for a substituted or unsubstituted alkyl group of 1 to 12 carbon atoms, a substituted or unsubstituted alkoxy group of 1 to 12 carbon atoms, a substituted or unsubstituted alkylamino group of 1 to 12 carbon atoms, a substituted or unsubstituted alkylthio group of 1 to 12 carbon atoms, a substituted or unsubstituted aryl group of 6 to 20 carbon atoms, a substituted or unsubstituted aryloxy group of 6 to20 carbon atoms, a substituted or unsubstituted arylamino group of 6 to 20 carbon atoms, or a substituted or unsubstituted arylthio group of 6 to 20 carbon atoms; R2stands for a divalent organic group; and n stands for a degree of polymerization.
These objects can be also accomplished by a method for the production of the polycyanoaryl ether of this invention which comprises polymerizing a tetrafluorobenzonitrile derivative represented by the formula (2): 
wherein R1 stands for a substituted or unsubstituted alkyl group of 1 to 12 carbon atoms, a substituted or unsubstituted alkoxy group of 1 to 12 carbon atoms, a substituted or unsubstituted alkylamino group of 1 to 12 carbon atoms, a substituted or unsubstituted alkylthio group of 1 to 12 carbon atoms, a substituted or unsubstituted aryl group of 6 to 20 carbon atoms, a substituted or unsubstituted aryloxy group of 6 to 20 carbon atoms, a substituted or unsubstituted arylamino group of 6 to 20 carbon atoms, or a substituted or unsubstituted arylthio group of 6 to 20 carbon atoms, with a dihydroxy compound represented by the formula (3):
HOxe2x80x94R2xe2x80x94OHxe2x80x83xe2x80x83(3)
wherein R2 stands for a divalent organic group, in the presence of a basic catalyst.
Since the polycyanoaryl ether of this invention has high mechanical strength and toughness, and excellent electrical properties, and also can manifest excellent solubility in various solvents which have generally used, excellent heat stability such as heat-resistance and flame-resistance, and excellent film-formability, it is a material which can be subjected to significantly general-use in the industrial field, such as a heat-resistant material, a composite material matrix for aerospace, a composite material matrix for nuclear reactor, an electrical insulating material, a composite material matrix for electromagnetic shield, a macromolecular electrolyte (separator) precursor for fuel cell, an optical material of wave guide, and the like.
Further, the polycyanoaryl ether of this invention can be easily and efficiently produced without any necessity of special equipments by subjecting a tetrafluorobenzonitrile derivative to the copolycondensation with a dihydroxy compound.
The above and other objects, features and advantages of the present invention will become clear from the following description of the preferred embodiments.